This application claims priority to Japanese Patent Application No. 2010-254593, filed Nov. 15, 2010, the entirety of which is incorporated herein by reference.
1. Technical Field
The present invention relates to printing systems that print images specified by rendering commands, and to correspondence relationship information creation methods for converting rendering commands.
2. Related Art
Thus far, systems that obtain a rendering command from CAD application software, generate bitmap data containing lines rendered in accordance with the rendering command, and form an image based on the bitmap data on a print medium have been known.
Japanese Patent No. 3770581 discloses preventing problems such as the disappearance of fine line image areas from within an image in a color image is printed in black and white using a low-resolution printer, by using both or either one of a halftone dot process and an error diffusion process in accordance with the characteristics of the line-shaped portions in the image (that is, the thickness, the darkness, and so on). JP-A-2010-91590, meanwhile, discloses a method related to barcode printing, where a barcode that can be read in a stable manner by a barcode reader is printed by correcting black line thicknesses that fluctuate due to a variety of causes, such as the environment (temperature, humidity, and so on), the passage of time, and so on. To create a reference for the correction of line thicknesses, a reference pattern that contains a plurality of black lines of the same thickness is printed, the darkness of the reference pattern is detected by a sensor, and the reference for the black line thickness of the barcode is determined based on the darkness signal. This technique discloses correcting the thicknesses of the black lines contained in the barcode to be printed based on the black line thicknesses of the reference that has been determined in this manner.
With the past techniques, there has been a problem in that in the case where diagrams created using CAD application software are printed on different printers, the visual thicknesses of the lines drawn in the diagrams have varied depending on the printer, which has led to the diagrams being mistakenly read. Depending on the resolution of the printer, restrictions unique to the printing process (bleeding, widening), and so on, it may not be possible to faithfully reproduce the line thicknesses specified in the rendering command. Furthermore, there are cases where the darkness of the printed materials differs from printer to printer even if a color of the same darkness is specified in the rendering command. Accordingly, variations such as those mentioned above have occurred in the case where the same diagram is printed using different printers. In JP-A-2010-91590, the black line thicknesses have been corrected by changing the size of the dots that configure the edges of the black lines in the thickness direction, changing the number of dots in the black lines in the thickness direction, and so on. However, it is difficult to cause microscopic line thicknesses to match across different printers (this is because it is not possible to adjust the position of a dot to a finer degree than the resolution of the printer, and there are typically only approximately three types of dot sizes, or large, medium, and small; in addition, the sizes of dots can also differ depending on the type of the printer). Furthermore, even if the microscopic line thicknesses could be caused to match, differences in the darkness of the recording agent itself used in the printers can arise depending on the type of the recording agent, and it is thus conceivable for the visual thickness of the lines to appear different to the human eye even if the microscopic line thicknesses match.